Thermal properties of calcium-aluminate based materials

Good cementing properties, fast setting and strong thermal performance make calcium aluminate a valuable raw material for use in the production of different types of new refractory materials, e.g., heat conductive/storage materials. The main aim of the study was to determine thermal properties of novel Nb-slag based materials with different fillers, and to clarify the optimal composition and technology. The preparation process of the studied materials was the following: mixing of components, casting into moulds and hardening of materials. To estimate potential application areas, the following thermal properties of CA-based materials were investigated: thermal behaviour, the coefficient of thermal expansion (CTE) and conductivity. For thermal analysis, small cylindrical specimens were cut out from produced materials, and plates sized 25 x 300 x 300 mm were used for conductivity studies. Different compositions of CA-based materials, the hardening process, and the influence of mechanical activation on the strength were analysed. The best thermal properties similar to the analogous reference materials were obtained by quartz sand and granite sand as filler materials. The thermal conductivity of the novel CA-based material is 1.5 times higher and the bending strength is about 3 times higher compared to commercial thermoplates.